1. Field of the Invention
The present invention relates to wireless communication systems which are applicable to time division duplex transceiver systems, and more particularly, to a time-division duplex wireless communication system capable of achieving miniaturization, low power consumption and low costs by using a frequency conversion circuit including a mixer, and an intermediate frequency (IF) circuit for both transmitter and receiver.
2. Description of the Related Art
Mobile communications services have recently provided a variety of services such as broadcasting services, multimedia video services, e-mail services and multimedia message services, investigating possibilities of creating a new market. These mobile communication services aim at realizing future-oriented mobile communication systems that provide data, voice and video services at a high speed when users of mobile communication terminals are not only stationary but also moving.
The users of mobile communication services demand the same quality of wireless multimedia services as in a wired broadband network. The users also require various quality of service (QoS) such as a high data rate or a low data rate and real-time or non-real-time in data transmitter/receiver.
The 4th generation mobile communication aims for fixed-mobile convergence (FMC)-based multimedia communication by achieving a data transmitter rate of maximum 100 Mbps when users of mobile communication terminals are moving at a high speed, and a data transmitter rate ranging from 155 Mbps to 1 Gbps when the users are moving at a low speed or are stationary. Accordingly, high channel capacity is required in data transmitter/receiver, and therefore broadband or multi-input multi-output (MIMO) technologies are needed.
More frequency bands are being used in communication due to the development of the wireless communication technologies, accordingly requiring a multi-band transceiver to be implemented as one chip and massive data to be transmitted at a high speed. An example of a related art transceiver system will now be described with reference to FIG. 1.
FIG. 1 is a block diagram of a related art transceiver system.
Referring to FIG. 1, the related art transceiver system includes a local oscillator 5, a transmitter 10 and a receiver 20.
The transmitter 10 includes a transmitter filter 11 passing a transmitter intermediate frequency (IF) signal in a low frequency band; a transmitter amplifier 12 amplifying the transmitter IF signal from the transmitter filter 11; a transmitter mixer 13 mixing the transmitter IF signal with an oscillation signal of the local oscillator 5 to convert the transmitter IF signal into a transmitter radio frequency (RF) signal; and a power amplifier 14 amplifying power of the transmitter RF signal from the transmitter mixer 13.
The receiver 20 includes an RF amplifier 21 amplifying an incoming receiver RF signal; a receiver mixer 22 mixing the receiver RF signal from the RF amplifier 21 with an oscillation signal from the local oscillator 5 to convert the receiver RF signal into a receiver IF signal; an IF filter 23 passing the receiver IF signal from the receiver mixer 22 in a low frequency band; and an IF amplifier 24 amplifying the receiver IF signal from the IF filter 23.
However, the related art transceiver system illustrated in FIG. 1 has limitations in achieving miniaturization, low power consumption and low manufacturing costs because the transmitter 10 and the receiver 20 are separately implemented therein.
That is, the related art transceiver system fails to overcome the above limitations in providing a high-speed large-capacity data communication service in multi-band, multi-application systems.